The present invention relates to metal working and in particular relates to metal can making.
The invention is especially useful in the manufacture of so called "two piece" cans. The language two piece is intended to denote cans having a top or closure fabricated from one piece of sheet metal and having a body and a contiguous bottom fabricated from a second piece of sheet metal.
More specifically, the invention relates to tools and dies useful to form peripheral chimes and beads and other impressions of various configurations upon can bodies in automatic fashion.
In prior art devices beads were added to round can bodies by a rolling action in which a can body was sandwiched between cooperating male and female rolling dies and a bead was worked into the can as the dies rolled about the can body. Alternatively, beads were formed by dies working through the open ends of a three piece (top, bottom and side walls made from separate blanks) can.
Prior art devices are shown in the following U.S. Pat. Nos. 1,740,196 to Muhlbach, 2,198,873 to Hinsdale, 2,313,749 to Hothersall, 2,579,919 to Funke, 3,726,121 to Arnold et al and 3,855,862 to Moller.
A particular feature of the present invention is the provision of a metal working tool useful to form body beads and chime beads in a two piece metal can of circular, rectangular, oval, triangular or irregular and unsymmetrical cross-section.
A further feature of the invention is the provision of a metal working tool useful to form random or regular impressions of any, desired configuration upon the body of a two piece can of circular, rectangular, oval, triangular or irregular and unsymmetrical cross-section.
A still further feature of the invention is the provision of a metal working tool useful to form internal (inwardly projecting relative to the can body sidewall) and external (outwardly projecting) impressions of any desired configuration.
A further feature of the invention is the provision of a plurality of groups or sets of segmental dies which are operative to move to and fro relative to a work piece (can body) in sequential fashion.
A further feature of the invention is the provision of a novel metal working tool including a plurality of segmental die sets which operate upon the interior and upon the exterior of a can body sequentially.
The working surfaces of said segmental dies correspond generally to the cross-sectional configuration of the can body. For example, if the can body is oval the working surfaces define an oval.
Note, too, that the scope of the present invention includes realization that the die segments of a given set may vary in number as considerations of good design dictate. For example, a set may be composed of two, three, four or more die segments as mechanical design considerations require.
A still further feature of the invention is the provision of a metal working tool which lends itself to inclusion, as an additional work station, in a conventional can press thereby precluding transfer of a finished can to a separate multiple head bead rolling tool for the beading operation.
A further feature of the invention is the provision of a metal forming tool operative to form a wide variety of beads or embossments upon a two piece metal can body. The language "beads" or "embossments" is intended to denote concave or convex impressions upon can bodies having round, rectangular, oval, triangular or irregular and unsymmetrical configuration in cross-section.
For example, die segments can be employed which create circular, vertical, spiral, inter-secting, random or patterned impressions upon a can body projecting to the interior or to the exterior of the can body wall as desired.
A further feature of the invention is the provision of a metal forming tool useful in the can making art operative to make random or regular impressions upon a can body where the impressions are effective to increase the can body's resistance to identation, crushing or axial compression.
A further feature to the invention is the provision of a metal working tool in the can making art operative to increase the structural integrity of the can body thereby facilitating the use of thinner gage can making stock than would be necessary in the absence of the present invention.
A still further feature of the invention is the provision of a metal working tool which precludes damage to coatings previously applied on one or both sides of a work piece.
Another feature of the invention is the provision of a metal working tool of the general class discussed above which facilitates changes in die sets when it is desired to change impressions or patterns of impressions.